Speech sound disorders (SSD) are the most prevalent type of communication disorder in early childhood and often place an individual at risk for later academic difficulties. Individuals whose SSD persists past 8 years of age are at highest risk for poor long-term social-emotional, academic, and vocational outcomes. To date, there have been no large prospective studies to identify genetic, hormonal, and behavioral risk factors for persistent SSD so that children at greatest risk may be identified and treated early with interventions to prevent later adverse effects. The present proposal is a continuation of a 25 year genetic study of SSD (A Familial Study of Severe Phonology Disorders; NIDCD grant number DC000528) that has identified risk genes for SSD and co- morbid language impairment (LI) and reading disorders (RD). We found a higher prevalence of the most severe forms of SSD in males compared to females. Genes identified in our prior work regulate estrogen levels involved in early brain development, which may account for gender differences in gene expression. In the proposed project we will explore hormonal differences in children with SSD as a potential biomarker to identify children at greatest risk for persistent SSD. Predictive models for persistent SSD will be built from risk genes, hormonal biomarkers, and five behavioral endophenotypes: deficits in speech motor control, phonological memory, phonological processing, speeded naming, and vocabulary. Three hundred children with early SSD will be examined for all factors at 4-6 years of age and again at 8-10 years of age. Findings will reveal predictors of long-term problems to which individuals with early SDD are vulnerable, identify risk factors, and determine deficits to target in early interventions to insure more favorable educational, vocational, and behavioral outcomes.